Recently, the thermal image transfer recording system is used in addition to the electrophotographic, ink jet and electrostatic recording system. As one of the thermal image transfer recording systems, the electric current-conducting system has been proposed. In this system, instead of giving thermal energy to the ink layer with a thermal head, electric current is conducted through an electroconductive film having a certain electric resistance, and the ink layer is melted or sublimated by the generated Joule's heat. For example, U.S. Pat. No. 4,103,066 discloses the use of a polycarbonate film containing carbon black as a base film of the material. Also, U.S. Pat No. 4,269,892 discloses the use of a polyester resin containing carbon black as the base film of the material. However, since the above-mentioned resins have poor affinity (wettability and the like) for the carbon black, the obtained films have poor mechanical characteristics. For example, as stated in U.S. Pat. No. 4,269,892, polycarbonate has small tensile elongation and the polyester has a tensile strength of as low as 4 kg/mm.sup.2. Further, if a large current is conducted for the purpose of high speed printing, since the heat resistance of the film is not sufficient, the film may be thermally deformed or pinholes may be formed in the film. Thus, it is difficult to conduct high speed printing which generates much heat. Further, to compensate for this disadvantage, the film should have a thickness as great as 15 .mu.m or more.